Three-dimensional co-axial linear photonic switch

Abstract

Techniques, systems, and devices are disclosed that relate to coaxial photoconductive switch modules. The coaxial photoconductive switch may include an outer conductor, an inner conductor, and a photoconductive material positioned between the inner conductor and the outer conductor. The inner conductor, the outer conductor, and the photoconductive material have a predetermined height. A bias voltage may be applied between the inner conductor and the outer conductor. When light of a predetermined wavelength and a predetermined intensity is incident on the photoconductive material, the photoconductive material may break down allowing a current to flow through the photoconductive material between the inner conductor and the outer conductor.

What is claimed is: 
     
       1. A high-voltage coaxial photoconductive device for switching a voltage or a current, comprising:
 a cylindrical outer conductor having an inner radius; 
 a cylindrical inner conductor having an outer radius; 
 a photoconductive material positioned between the outer radius of the inner conductor and the inner radius of the outer conductor, wherein the inner conductor and the outer conductor are configured to establish an electric field across the photoconductive material upon application of a voltage value between the inner and the outer conductors; and 
 a light source having a particular wavelength or range of wavelengths, the light source coupled to the photoconductive material to inject light into the photoconductive material, wherein the photoconductive material is shaped to have a height to allow the light to propagate from the light source through a substantial entirety of the height of the photoconductive material and to be absorbed by the photoconductive material with a corresponding absorption efficiency, thereby causing the photoconductive material to break down and to become conductive and a current to flow through the photoconductive material between the inner conductor and the outer conductor, 
 wherein the photoconductive material is configured to break down at a breakdown voltage based on properties of the photoconductive material and a thickness of the photoconductive material, the thickness of the photoconductive material determined based on the inner radius of the outer conductor and the outer radius of the inner conductor. 
 
     
     
       2. The coaxial photoconductive device as in  claim 1 , wherein the inner conductor and the outer conductor are formed from a material that includes one or more of the following metals: titanium, gold, aluminum, silver, platinum, chromium, or copper, or one or more conductive ceramics including indium tin oxide (ITO), aluminum doped zinc oxide (AZO), or fluorine doped tine oxide (FTO). 
     
     
       3. The coaxial photoconductive device as in  claim 2 , wherein the inner cylinder is formed as a solid cylinder of the material. 
     
     
       4. The coaxial photoconductive device as in  claim 1 , wherein the photoconductive material includes one or more of: silicon, germanium, silicon carbide, diamond, gallium nitride, gallium arsenide, gallium phosphide, aluminum nitride, boron nitride, zinc oxide, or cadmium telluride. 
     
     
       5. The coaxial photoconductive device as in  claim 1 , wherein the height of the photoconductive material is determined based on one or more of: the wavelength or range of wavelengths of the light source, the inner radius of the outer conductor, the outer radius of the inner conductor, or the voltage value between the inner and the outer conductors. 
     
     
       6. The coaxial photoconductive device as in  claim 1 , wherein the height for the coaxial structure is selected to produce a predetermined absorption efficiency in the photoconductive material. 
     
     
       7. The coaxial photoconductive device as in  claim 1 , wherein the thickness of the photoconductive material is equal to the difference between the outer radius of the inner conductor and the inner radius of the outer conductor, and wherein the thickness is selected to produce a predetermined breakdown voltage. 
     
     
       8. The coaxial photoconductive device as in  claim 1 , wherein the height is selected to cause, at a predetermined minimum light intensity at the particular wavelength or the range of wavelengths, the photoconductive material to break down. 
     
     
       9. The coaxial photoconductive device as in  claim 1 , wherein the outer conductor, the inner conductor, and the photoconductive material are each shaped to have the same height. 
     
     
       10. The coaxial photoconductive device as in  claim 1 , configured to allow light from the light source travel through the photoconductive material along a longitudinal axis of the photoconductive material. 
     
     
       11. The coaxial photoconductive device as in  claim 1 , wherein the light source is configured to illuminate the photoconductive material from a first end of the photoconductive material so that the light from the light source propagates substantially parallel to a longitudinal axis of the photoconductive material. 
     
     
       12. A high-voltage photoconductive device for switching a voltage or a current, comprising:
 an outer electrode; 
 an inner electrode; and 
 a photoconductive material positioned between inner electrode and the outer electrode, wherein:
 the inner electrode and the outer electrode are configured to allow an electric field to be established across the photoconductive material upon application of a voltage between the inner and the outer electrodes, and 
 the photoconductive material is shaped to have a height to allow, upon injection of light having a particular wavelength or range of wavelengths into the photoconductive material, the light to propagate through a substantial entirety of the height of the photoconductive material and to be absorbed by the photoconductive material with a corresponding absorption efficiency, thereby causing the photoconductive material to break down and a current to flow through the photoconductive material between the inner electrode and the outer electrode, 
 
 wherein the photoconductive material is configured to break down at a breakdown voltage based on properties of the photoconductive material and a thickness of the photoconductive material, the thickness of the photoconductive material determined based on sizes of the inner electrode and the outer electrode. 
 
     
     
       13. The photoconductive device of  claim 12 , wherein the outer electrode and the inner electrode have a circular cross-sectional shape. 
     
     
       14. The photoconductive device of  claim 12 , wherein the outer electrode and the inner electrode have a square cross-sectional shape. 
     
     
       15. The photoconductive device of  claim 12 , wherein the outer electrode and the inner electrode have a polygonal cross-sectional shape.